[PATCH] convert /proc/devices to use seq_file interface
A Christoph suggested that the /proc/devices file be converted to use the
seq_file interface. This patch does that.
I've obxerved one or two installation that had sufficiently large sans that
they overran the 4k limit on /proc/devices.
Signed-off-by: Neil Horman <nhorman@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/block/genhd.c b/block/genhd.c
index f1ed83f..db57546 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -38,34 +38,100 @@
return major % MAX_PROBE_HASH;
}
-#ifdef CONFIG_PROC_FS
-/* get block device names in somewhat random order */
-int get_blkdev_list(char *p, int used)
+struct blkdev_info {
+ int index;
+ struct blk_major_name *bd;
+};
+
+/*
+ * iterate over a list of blkdev_info structures. allows
+ * the major_names array to be iterated over from outside this file
+ * must be called with the block_subsys_sem held
+ */
+void *get_next_blkdev(void *dev)
+{
+ struct blkdev_info *info;
+
+ if (dev == NULL) {
+ info = kmalloc(sizeof(*info), GFP_KERNEL);
+ if (!info)
+ goto out;
+ info->index=0;
+ info->bd = major_names[info->index];
+ if (info->bd)
+ goto out;
+ } else {
+ info = dev;
+ }
+
+ while (info->index < ARRAY_SIZE(major_names)) {
+ if (info->bd)
+ info->bd = info->bd->next;
+ if (info->bd)
+ goto out;
+ /*
+ * No devices on this chain, move to the next
+ */
+ info->index++;
+ info->bd = (info->index < ARRAY_SIZE(major_names)) ?
+ major_names[info->index] : NULL;
+ if (info->bd)
+ goto out;
+ }
+
+out:
+ return info;
+}
+
+void *acquire_blkdev_list(void)
+{
+ down(&block_subsys_sem);
+ return get_next_blkdev(NULL);
+}
+
+void release_blkdev_list(void *dev)
+{
+ up(&block_subsys_sem);
+ kfree(dev);
+}
+
+
+/*
+ * Count the number of records in the blkdev_list.
+ * must be called with the block_subsys_sem held
+ */
+int count_blkdev_list(void)
{
struct blk_major_name *n;
- int i, len;
+ int i, count;
- len = snprintf(p, (PAGE_SIZE-used), "\nBlock devices:\n");
+ count = 0;
- down(&block_subsys_sem);
for (i = 0; i < ARRAY_SIZE(major_names); i++) {
- for (n = major_names[i]; n; n = n->next) {
- /*
- * If the curent string plus the 5 extra characters
- * in the line would run us off the page, then we're done
- */
- if ((len + used + strlen(n->name) + 5) >= PAGE_SIZE)
- goto page_full;
- len += sprintf(p+len, "%3d %s\n",
- n->major, n->name);
- }
+ for (n = major_names[i]; n; n = n->next)
+ count++;
}
-page_full:
- up(&block_subsys_sem);
- return len;
+ return count;
}
-#endif
+
+/*
+ * extract the major and name values from a blkdev_info struct
+ * passed in as a void to *dev. Must be called with
+ * block_subsys_sem held
+ */
+int get_blkdev_info(void *dev, int *major, char **name)
+{
+ struct blkdev_info *info = dev;
+
+ if (info->bd == NULL)
+ return 1;
+
+ *major = info->bd->major;
+ *name = info->bd->name;
+ return 0;
+}
+
int register_blkdev(unsigned int major, const char *name)
{